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Castellanos N.T.,Escuela Colombiana de Ingenieria | Agredo J.T.,National University of Colombia
Ingenieria e Investigacion | Year: 2010

Spent fluid catalytic cracking (FCC) catalyst is an oil industry by-product from fluidised-bed catalytic cracking units. This residue is mainly formed by an active component (faujasite type zeolite Y) in an amorphous aluminosilicate matrix. It mainly consists of up to 90% silica and alumina. This paper reports an extensive literature review regarding the characterisation and mechanical and durability properties of mortar and concrete added to this material. FCC has been studied lately due to its pozzolanic characteristics and the good performance of concrete mixtures using FCC as cement replacement.

Chaparro J.A.,Escuela Colombiana de Ingenieria
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference | Year: 2011

One of the most challenging problems in intensive care is the process of discontinuing mechanical ventilation, called weaning process. An unnecessary delay in the discontinuation process and an early weaning trial are undesirable. This paper proposes to analysis the respiratory pattern variability of these patients using autoregressive modeling techniques: autoregressive models (AR), autoregressive moving average models (ARMA), and autoregressive models with exogenous input (ARX). A total of 153 patients on weaning trials from mechanical ventilation were analyzed: 94 patients with successful weaning (group S); 38 patients that failed to maintain spontaneous breathing (group F), and 21 patients who had successful weaning trials, but required reintubation in less than 48 h (group R). The respiratory pattern was characterized by their time series. The results show that significant differences were obtained with parameters as model order and first coefficient of AR model, and final prediction error by ARMA model. An accuracy of 86% (84% sensitivity and 86% specificity) has been obtained when using order model and first coefficient of AR model, and mean of breathing duration.

Ladino L.A.,Escuela Colombiana de Ingenieria
Physics Education | Year: 2013

A different method to study the charging and discharging processes of a capacitor is presented. The method only requires a high impedance voltmeter. © 2013 IOP Publishing Ltd.

Torres Castellanos N.,Escuela Colombiana de Ingenieria | Torres Agredo J.,National University of Colombia | Mejia de Gutierrez R.,University of Valle
Ingenieria e Investigacion | Year: 2013

In this work the evaluation of the performance of concrete added with Fluid Catalytic Cracking Catalyst residue (FCC) from a Colombian petroleum company, under sulfate attack, is presented. The results of this concrete are compared with the results of Me-takaolin (MK) added concrete. The analysis of the pozzolanic materials included the determination of the particle size, the poz-zolanic activity and the chemical and mineralogical composition. Different percentages of FCC were used as Portland cement replacement in proportions of 0, 10, 20 and 30%; similarly concrete added with 20% of MK as replacement was elaborated. Com-pressive strength and performance under sulfate attack were evaluated. Results showed that concrete with FCC and MK as well as control concrete had similar behavior; however its expansion was higher. In addition, the performance of the two types of concrete (FCC y MK) under sulfate attack was comparable; this could be due to fact that FCC and MK showed similarities regarding of their chemical and mineralogical composition. Importantly, after 360 days of exposure the specimens with MK and FCC showed no significant deterioration.

Archilla A.R.,University of Hawaii at Manoa | Diaz L.G.,Escuela Colombiana de Ingenieria
Transportation Research Record | Year: 2011

The hot-mix asphalt (HMA) rutting prediction model in the Mechanistic-Empirical Pavement Design Guide (MEPDG) uses a relationship that includes the effects of mix characteristics only through the resilient strain, which in turn is a function of the dynamic modulus (|E*|) of the mix. However, increasing evidence suggests that the use of |E*| alone may be insufficient to characterize completely the permanent deformation behavior of HMA. In addition to effects already considered by the MEPDG model with |E*|, the effects of mix characteristics on permanent deformation are analyzed with the use of the results of repetitive axial permanent deformation tests from laboratory-compacted HMA specimens. Results of multiple linear regression analysis indicate that binder type, effective binder content, and air void content have significant effects on model parameters for permanent deformation. The potential effects of mix characteristics on these parameters are analyzed with the use of the MEPDG model and an HMA pavement section with four levels of compaction. Scenarios in which the mixture characteristics are incorporated solely by means of |E*| are compared with scenarios in which the effects of air void content and asphalt content are incorporated into the rutting prediction model by adjusting its parameters according to relationships established in the laboratory. Empirical laboratory evidence supports the hypotheses that, regardless of mixture properties, universal values for permanent deformation model parameters do not fully account for mixture-specific contributions to rutting and that other mix characteristics (e.g., air void content) may be needed to supplement |E*| for the appropriate characterization of the permanent deformation of asphalt mixtures.

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